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<li class="toctree-l4 current"><a class="current reference internal" href="#"><code class="docutils literal notranslate"><span class="pre">category_property/2</span></code></a></li>
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  <p class="align-right"><strong>built-in predicate</strong></p>
<section id="category-property-2">
<span id="predicates-category-property-2"></span><span id="index-0"></span><h1><code class="docutils literal notranslate"><span class="pre">category_property/2</span></code><a class="headerlink" href="#category-property-2" title="Link to this heading"></a></h1>
<section id="description">
<h2>Description<a class="headerlink" href="#description" title="Link to this heading"></a></h2>
<div class="highlight-logtalk notranslate"><div class="highlight"><pre><span></span><span class="k">category_property</span>(<span class="nv">Category</span>, <span class="nv">Property</span>)
</pre></div>
</div>
<p>Enumerates, by backtracking, the properties associated with the defined
categories. The valid properties are listed in the language grammar section
on <a class="reference internal" href="../grammar.html#grammar-entity-properties"><span class="std std-ref">entity properties</span></a> and described in
the User Manual section on <a class="reference internal" href="../../userman/categories.html#categories-properties"><span class="std std-ref">category properties</span></a>.</p>
</section>
<section id="modes-and-number-of-proofs">
<h2>Modes and number of proofs<a class="headerlink" href="#modes-and-number-of-proofs" title="Link to this heading"></a></h2>
<div class="highlight-logtalk notranslate"><div class="highlight"><pre><span></span><span class="k">category_property</span>(<span class="o">?</span>category_identifier, <span class="o">?</span>category_property) <span class="o">-</span> zero_or_more
</pre></div>
</div>
</section>
<section id="errors">
<h2>Errors<a class="headerlink" href="#errors" title="Link to this heading"></a></h2>
<div class="line-block">
<div class="line"><code class="docutils literal notranslate"><span class="pre">Category</span></code> is neither a variable nor a valid category identifier:</div>
<div class="line-block">
<div class="line"><code class="docutils literal notranslate"><span class="pre">type_error(category_identifier,</span> <span class="pre">Category)</span></code></div>
<div class="line"><br /></div>
</div>
<div class="line"><code class="docutils literal notranslate"><span class="pre">Property</span></code> is neither a variable nor a callable term:</div>
<div class="line-block">
<div class="line"><code class="docutils literal notranslate"><span class="pre">type_error(callable,</span> <span class="pre">Property)</span></code></div>
</div>
<div class="line"><code class="docutils literal notranslate"><span class="pre">Property</span></code> is a callable term but not a valid category property:</div>
<div class="line-block">
<div class="line"><code class="docutils literal notranslate"><span class="pre">domain_error(category_property,</span> <span class="pre">Property)</span></code></div>
</div>
</div>
</section>
<section id="examples">
<h2>Examples<a class="headerlink" href="#examples" title="Link to this heading"></a></h2>
<div class="highlight-logtalk notranslate"><div class="highlight"><pre><span></span><span class="c">% enumerate the properties of the core_messages built-in category:</span>
| <span class="o">?-</span> <span class="k">category_property</span>(core_messages, <span class="nv">Property</span>).

<span class="nv">Property</span> <span class="o">=</span> source_data <span class="o">;</span>
<span class="nv">Property</span> <span class="o">=</span> static <span class="o">;</span>
<span class="nv">Property</span> <span class="o">=</span> built_in <span class="o">;</span>
...
</pre></div>
</div>
<div class="admonition seealso">
<p class="admonition-title">See also</p>
<p><a class="reference internal" href="abolish_category_1.html#predicates-abolish-category-1"><span class="std std-ref">abolish_category/1</span></a>,
<a class="reference internal" href="create_category_4.html#predicates-create-category-4"><span class="std std-ref">create_category/4</span></a>,
<a class="reference internal" href="current_category_1.html#predicates-current-category-1"><span class="std std-ref">current_category/1</span></a>,
<a class="reference internal" href="complements_object_2.html#predicates-complements-object-2"><span class="std std-ref">complements_object/2</span></a>,
<a class="reference internal" href="extends_category_2_3.html#predicates-extends-category-2-3"><span class="std std-ref">extends_category/2-3</span></a>,
<a class="reference internal" href="imports_category_2_3.html#predicates-imports-category-2-3"><span class="std std-ref">imports_category/2-3</span></a></p>
</div>
</section>
</section>


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